abbrev-insert is a compiled Lisp function in `
(abbrev-insert ABBREV &optional NAME WORDSTART WORDEND)
Insert abbrev ABBREV at point.
If non-nil, NAME is the name by which this abbrev was found.
If non-nil, WORDSTART is the place where to insert the abbrev.
If WORDEND is non-nil, the abbrev replaces the previous text between
WORDSTART and WORDEND.
Return ABBREV if the expansion should be considered as having taken place.
The return value can be influenced by a `no-self-insert' property;
see `define-abbrev' for details.